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Thread: Raypak heater whining... how to increase water flow?

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    Raypak heater whining... how to increase water flow?

    I bought a Raypak heater for my new AG pool last summer, based largely on advice from ps0303 (Paul) that I read in this forum. It works great. Thanks, Paul! However, it makes a whining/whistling noise. Iím pretty sure the noise is caused by insufficient water flow (thanks again to Paulís posts). Iíd like advice on the best course of action. Here are some options Iím considering:

    • Live with it. The noise is a minor annoyance. Apparently the real downside is not the noise itself, but the fact that itís a symptom of the temperature being too high inside the heater, which can accelerate scale buildup. Would this be very likely to shorten my heater's life?
    • Set the filter multiport to recirculate when heating. I tried this for a few minutes, and the noise was almost eliminatedóreduced to an occasional very quiet squeak. But that would send unfiltered water through the heater. Bad idea, right?
    • Optimize plumbing layout. The pool builder used 1.5Ē flexible hose, and I added a heater bypass made of 2Ē PVC. The flexible hose has some tight turns that could be improved by adding supports, and thereís a 90 degree elbow at the pump inlet that points away from the skimmer (***?) that I think should be eliminated anyway.
    • Replace all 1.5Ē flexible hose with 2Ē PVC. Could this increase flow rate substantially?
    • Upgrade my 1HP pump. Iíd likely go to a 1.5HP VS and run it at a much lower speed when not heating. My concern here is whether I could damage my filter. My SD40 sand filter is rated for 40gpm maximum, according to the brochure on the Pentair website. I fear that I may be caught between a rock and a hard placeÖ maybe the filter canít handle the water flow that the heater needs? Will I need to upgrade both the pump and filter to satisfy the heaterís water flow demand?


    One more related question: besides low flow, the other documented cause of whistling in the Raypak heaters is a faulty unitherm governor (UG). I removed mine and tested it in a bowl of hot water and it expanded like itís supposed to. However, the UG gasket was twisted. I straightened it and lubed it, but itís still crimped and imperfect. Is there any chance that a new gasket would solve the noise problem?

    Thanks in advance for any and all advice.
    Sharkline Oceanic AG pool: 14.2k gallon, 15'x30' oval, built 7/17/14
    Pentair SD40 sand filter w/ 1HP dual-speed OptiFlo pump
    Raypak 266k BTU NG heater
    TF100 test kit

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    Re: Raypak heater whining... how to increase water flow?

    Issues with the unitherm governor have been more of an issue with their professional series. Seems like you tested it right and it's working as it should. The gasket you speak of is common and an annoyance for sure. No lube is really needed for that gasket.

    I would get rid of the flex hose as much as possible. Use the correct PVC piping as much as possible. I know is common on AGP pools but it can create issue especially since you can twist and bend it more than it should. Your pump size is adequate and I would not worry about upgrading it.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Raypak heater whining... how to increase water flow?

    Thanks, Paul. It's a relief to know that I don't need a new pump. I will start taking measurements and working on a plan for new plumbing in 2" PVC.
    Sharkline Oceanic AG pool: 14.2k gallon, 15'x30' oval, built 7/17/14
    Pentair SD40 sand filter w/ 1HP dual-speed OptiFlo pump
    Raypak 266k BTU NG heater
    TF100 test kit

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    Re: Raypak heater whining... how to increase water flow?

    The plot thickens: I just found a way to eliminate the whining noise without setting the multiport to recirculate. But I'd like expert opinions on why it worked and if it's ok to run it this way.

    My heater bypass is made of 2" PVC and includes 3 ball valves. I read in another thread that a Raypak owner made the noise go away by increasing back pressure. So I tried the same thing by slowly closing the valve just downstream from the heater while the heater was running. The noise got quieter as I went and stopped altogether when the valve was about 2/3 closed. I checked the flow at the return eyeball and found it reduced but still decent... I'd say similar to the way it feels when my filter is due for a backwash.

    I'm confused because I'd already tried reducing flow to the heater by opening the bypass and got a very different result. The noise dropped in pitch (the valve was like a musical instrument) and got even louder.

    Here are my questions:

    1. Can too much water flow cause a whining noise? If so, why?
    2. How come restricting flow upstream of the heater (opening the bypass) doesn't stop the noise, but restricting it downstream does?
    3. Would I be introducing any risk by running it this way all the time (with the ball valve partially closed)?
    Sharkline Oceanic AG pool: 14.2k gallon, 15'x30' oval, built 7/17/14
    Pentair SD40 sand filter w/ 1HP dual-speed OptiFlo pump
    Raypak 266k BTU NG heater
    TF100 test kit

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    Re: Raypak heater whining... how to increase water flow?

    Bump. Any thoughts on the effect of restricting flow downstream of the heater.
    Sharkline Oceanic AG pool: 14.2k gallon, 15'x30' oval, built 7/17/14
    Pentair SD40 sand filter w/ 1HP dual-speed OptiFlo pump
    Raypak 266k BTU NG heater
    TF100 test kit

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    Re: Raypak heater whining... how to increase water flow?

    I wouldn't want to restrict the flow.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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